Recently, it has been reported that the monitoring of acidity or pH of a patient's breath could help physicians in estimating the potential for and occurrence of asthma, laryngopharyngeal reflux disease (LPRD), aspiration-related lung diseases, chronic obstructive pulmonary disease (COPD), and sleep related breathing disorders such as obstructive sleep apnea (OSA).
Gastroesophageal reflux in the airway is associated with, and known to exacerbate, widespread respiratory diseases such as asthma, laryngopharyngeal reflux disease (LPRD), aspiration-related lung diseases, chronic obstructive pulmonary disease (COPD), and sleep related breathing disorders such as obstructive sleep apnea (OSA). Reflux in the airway is also prevalent in infants and children as well as intubated or sedated patients in whom current pH diagnostic procedures are contraindicated. In extreme cases, the exposure of acid reflux into the respiratory system can lead to aspiration pneumonia or acute respiratory distress.
Given the current state of commercialized products, clinicians are limited in their ability to test pH in the respiratory tract. Evaluation of patient pH can be conducted by a qualified physician in a typical 24 hour pH study, using a pH measurement catheter. The presently available pH monitoring and diagnostic devices require insertion of a pH measurement catheter through a patient's nose, past the epiglottis, through the upper esophageal sphincter (UES), and into the esophagus. These catheters are comprised of a pH sensor and reference sensor at the catheter distal end, and require immersion in liquid to function effectively. The devices have invasive or uncomfortable consequences for the patient. Because they pass through the larynx and into the esophagus, discomfort during swallowing, talking, and movement can occur. A recently introduced product, the Medtronic Bravo™, is a catheter based device that requires attachment of a pH measurement capsule to the esophagus wall. The product requires a larger diameter trans-nasal catheter to place the capsule. Because these methods are invasive and uncomfortable, only a small percentage of prospective patients are able to undergo pH monitoring.
Placement of esophageal catheters requires special expertise to identify the physical landmarks required for proper catheter placement. Typically, pressure measurements are conducted to find the lower esophageal sphincter and upper esophageal sphincter, with endoscopic confirmation of placement required in some cases.
Traditional pH catheters used to conduct measurements of pH in the patient's laryngeal region and have several limitations when placed in the upper airway. They are capable of only measuring liquid reflux events which extend past the UES. They are subject to becoming fouled, contaminated or embedded in the mucosal wall. If placed higher in the airway, the sensor can become dehydrated, losing electrical continuity with the reference electrode. In these cases, the accuracy and reliability of the pH, measurements are compromised.
Accordingly, there is a need for a novel pH monitoring system with electronic or wireless communication linked to a processing receiver with data recording capability that can reliably measure and record pH in the patient's airway in real time.